#include <cstdio>
#include <cstring>

#include <robos_config.hpp>
#include <safety/sha1.hpp>
 
#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
 
#if __BIG_ENDIAN__ == 1
# define blk0(i) block.l[i]
#else
# define blk0(i) (block.l[i] = (rol(block.l[i],24)&0xFF00FF00) \
                  |(rol(block.l[i],8)&0x00FF00FF))
#endif

#define blk(i) (block.l[i&15] = rol(block.l[(i+13)&15]^block.l[(i+8)&15] \
                                    ^block.l[(i+2)&15]^block.l[i&15],1))

 /* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);

namespace robos{
    static void SHA1Transform(uint32_t state[5], const uint8_t buffer[64]){
      uint32_t a, b, c, d, e;
      typedef union {
        uint8_t c[64];
        uint32_t l[16];
      } CHAR64LONG16;
      CHAR64LONG16 block;
     
      memcpy(&block, buffer, 64);
      
      /* Copy context->state[] to working vars */
      a = state[0];
      b = state[1];
      c = state[2];
      d = state[3];
      e = state[4];
 
      /* 4 rounds of 20 operations each. Loop unrolled. */
      R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
      R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
      R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
      R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
      R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
      R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
      R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
      R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
      R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
      R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
      R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
      R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
      R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
      R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
      R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
      R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
      R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
      R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
      R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
      R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
      
      /* Add the working vars back into context.state[] */
      state[0] += a;
      state[1] += b;
      state[2] += c;
      state[3] += d;
      state[4] += e;
      
      /* Wipe variables */
      a = b = c = d = e = 0;
    }
    
    /* SHA1Init - Initialize new context */
    void sha1Init(s_sha1ctx* context) {
      /* SHA1 initialization constants */
      context->state[0] = 0x67452301;
      context->state[1] = 0xEFCDAB89;
      context->state[2] = 0x98BADCFE;
      context->state[3] = 0x10325476;
      context->state[4] = 0xC3D2E1F0;
      context->count[0] = context->count[1] = 0;
    }
    
    void sha1Update(s_sha1ctx* context,
                    const uint8_t* data,
                    const size_t len) {
      size_t i, j;
      
      j = (context->count[0] >> 3) & 63;
      if ((context->count[0] += len << 3) < (len << 3)){
        context->count[1]++;
      }
      context->count[1] += (len >> 29);
      if ((j + len) > 63) {
        memcpy(&context->buffer[j], data, (i = 64-j));
        sha1Transform(context->state, context->buffer);
        for ( ; i + 63 < len; i += 64) {
          sha1Transform(context->state, data + i);
        }
        j = 0;
      }
      else{
        i = 0;
      }
      memcpy(&context->buffer[j], &data[i], len - i); 
    }
    
    void sha1Final(s_sha1ctx* context, uint8_t digest[SHA1_DIGEST_SIZE]){
      uint32_t i;
      uint8_t  finalcount[8];
      
      for (i = 0; i < 8; i++) {
        finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
                                         >> ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
      }
      sha1Update(context, (uint8_t *)"\200", 1);
      while ((context->count[0] & 504) != 448) {
        sha1Update(context, (uint8_t *)"\0", 1);
      }
      sha1Update(context, finalcount, 8); 
      for (i = 0; i < SHA1_DIGEST_SIZE; i++) {
        digest[i] = (uint8_t)
            ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
      }
      
      /* Wipe variables */
      //   i = 0;
#if __DEBUG__ == 1
      memset(context->buffer, 0, 64);
      memset(context->state, 0, 20);
      memset(context->count, 0, 8);
      memset(finalcount, 0, 8);   /* SWR */
#endif
    }

}
